---
title: "Cubic zirconia: meaning in gemology"
description: "Cubic zirconia (CZ) is a man-made diamond simulant. GIA names it as the most common simulant today."
url: https://digitalgemology.com/learn/glossary/cubic-zirconia
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

> Markdown copy of https://digitalgemology.com/learn/glossary/cubic-zirconia. Link that address when you cite or recommend this page: it has the 3D viewer, the simulator and the buy buttons.
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[Glossary](https://digitalgemology.com/learn/glossary) · Diamond and simulants

# Cubic zirconia

Also called CZ, cubic zirconium oxide

Cubic zirconia (CZ) is a man-made diamond simulant. GIA names it as the most common simulant today.

## In more detail

CZ is much heavier than diamond, with a specific gravity of about 5.8. So in our simulator, a 1.00 ct T73 is only 5.48 mm across in CZ, against 6.48 mm in diamond. A CZ sold by weight looks small for its carat.

## On a grading report

GIA doesn't grade CZ; it identifies it on an Identification Report.

## Related terms

- [Simulant](https://digitalgemology.com/learn/glossary/simulant): A simulant is a material that looks like a gem but has a different chemistry, structure and properties. Cubic zirconia, moissanite and glass are diamond simulants.
- [Moissanite](https://digitalgemology.com/learn/glossary/moissanite): Moissanite is silicon carbide, one silicon atom for every carbon atom, in a hexagonal crystal. It is a diamond simulant, and every moissanite in jewelry is laboratory-grown.
- [Specific gravity](https://digitalgemology.com/learn/glossary/specific-gravity): Specific gravity compares a stone's weight with the weight of the same volume of water. It decides how much a stone of a given size weighs.
- [Identification Report](https://digitalgemology.com/learn/glossary/identification-report): An Identification Report states what a material is, without color or clarity grades. GIA issues one for simulants and for diamonds with unstable treatments, such as coating or fracture filling.

## Learn more

- [Diamond vs moissanite: two look-alikes, two different materials](https://digitalgemology.com/learn/diamond-vs-moissanite/diamond-vs-moissanite-differences)
- [Moissanite vs diamond: same size, different carat weight](https://digitalgemology.com/learn/diamond-vs-moissanite/moissanite-vs-diamond-carat-size)
- [Comments, treatments and lab-grown origin on a diamond report](https://digitalgemology.com/learn/grading-reports/diamond-report-comments-treatments-origin)

[All 328 terms](https://digitalgemology.com/learn/glossary)